Posterior Capsule Opacification after Cataract Surgery via Implantation with Hydrophobic Acrylic Lens Compared with Silicone Intraocular Lens: A Systematic Review and Meta-Analysis

Application of Silicone in Ophthalmology: A Review

This paper reviews the latest trends and applications of silicone in ophthalmology, especially related to intraocular lenses (IOLs). Silicone, or siloxane elastomer, as a synthetic polymer, has excellent biocompatibility, high chemical inertness, and hydrophobicity, enabling wide biomedical applications. The physicochemical properties of silicone are reviewed. A review of methods for mechanical and in vivo characterization of IOLs is presented as a prospective research area, since there are only a few available technologies, even though these properties are vital to ensure medical safety and suitability for clinical use, especially if long-term function is considered. IOLs represent permanent implants to replace the natural lens or for correcting vision, with the first commercial foldable lens made of silicone. Biological aspects of posterior capsular opacification have been reviewed, including the effects of the implanted silicone IOL. However, certain issues with silicone IOLs are still challenging and some conditions can prevent its application in all patients. The latest trends in nanotechnology solutions have been reviewed. Surface modifications of silicone IOLs are an efficient approach to further improve biocompatibility or to enable drug-eluting function. Different surface modifications, including coatings, can provide long-term treatments for various medical conditions or medical diagnoses through the incorporation of sensory functions. It is essential that IOL optical characteristics remain unchanged in case of drug incorporation and the application of nanoparticles can enable it. However, clinical trials related to these advanced technologies are still missing, thus preventing their clinical applications at this moment.

Effect of surface-modified intraocular lenses on long-term postoperative inhibition of posterior capsule opacification

We compared the posterior capsule opacification incidences at 5 years postoperatively and the neodymium-yttrium-aluminum-garnet capsulotomy rates at 10 years postoperatively for two types of intraocular lenses with different optical properties and shapes. This randomized, controlled, prospective, single-blinded study with intra-individual comparisons was conducted between July 21, 2009, and August 31, 2011, at the Dokkyo Medical University Hospital, Tochigi, Japan. Thirty patients (60 eyes) underwent bilateral cataract surgery and received a XY1 intraocular lens in one eye and a FY-60AD intraocular lens in the other. Both intraocular lenses are acrylic and manufactured by HOYA. The XY1 lens is a single-piece, tinted intraocular lens featuring an ultraviolet/ozone treatment on the posterior surface of the lens optic, aimed at enhancing posterior capsule adhesion to prevent posterior capsule opacification. Conversely, the FY-60AD is a tinted intraocular lens with modified polymethylmethacrylate C-loops and no ultraviolet/ozone treatment of the optic. Scheimpflug images were taken using EAS-1000 (NIDEK Co., Ltd., Aichi, Japan), and the scattered light intensity (computer compatible tape) on the posterior surface of the intraocular lens was calculated and evaluated as the posterior capsule opacification. The scattered light values of the XY1 and FY-60AD groups were 6.50 ± 5.69 and 11.64 ± 5.30 computer compatible tape, respectively, at 5 years postoperatively. The cumulative survival incidence after neodymium-yttrium-aluminum-garnet laser capsulotomy was 74.8 % in the XY1 group and 13.8 % in the FY-60AD group at 10 years postoperatively. The surface-modified intraocular lens XY1 reduced the incidence of posterior capsule opacification even 10 years after surgery. Surface modification to increase the adhesion between the intraocular lens and the capsule effectively prevents posterior capsule opacification.

Refractive lens exchange: What are the red lines?

Practical advancements in phacoemulsification techniques and intraocular lenses and the wide availability of phacoemulsification machines have led refractive lens exchange (RLE) to increase in popularity. Ethical boundaries in RLE have subsequently been pushed to include patients at higher risk of complications. In this editorial, we consider RLE outcomes and complications per type of refractive error, together with preoperative, intraoperative and postoperative ethical obligations for refractive surgeons. In the conclusions section, we propose an algorithm for ethics-guided indications to RLE.

Seeing the Future: A Review of Ocular Therapy

Ocular diseases present a unique challenge and opportunity for therapeutic development. The eye has distinct advantages as a therapy target given its accessibility, compartmentalization, immune privilege, and size. Various methodologies for therapeutic delivery in ocular diseases are under investigation that impact long-term efficacy, toxicity, invasiveness, and delivery range. While gene, cell, and antibody therapy and nanoparticle delivery directly treat regions that have been damaged by disease, they can be limited in the duration of the therapeutic delivery and have a focal effect. In contrast, contact lenses and ocular implants can more effectively achieve sustained and widespread delivery of therapies; however, they can increase dilution of therapeutics, which may result in reduced effectiveness. Current therapies either offer a sustained release or a broad therapeutic effect, and future directions should aim toward achieving both. This review discusses current ocular therapy delivery systems and their applications, mechanisms for delivering therapeutic products to ocular tissues, advantages and challenges associated with each delivery system, current approved therapies, and clinical trials. Future directions for the improvement in existing ocular therapies include combination therapies, such as combined cell and gene therapies, as well as AI-driven devices, such as cortical implants that directly transmit visual information to the cortex.

Light adjustable intraocular lenses in cataract surgery: considerations

PURPOSE OF REVIEW

Light adjustable intraocular lens (LAL) is a promising concept in cataract surgery. This review explores considerations for the use of LALs.

RECENT FINDINGS

Through updates, the safety of LALs and light delivery devices have been enhanced, enabling more efficient treatment with lower ultraviolet (UV) energy. Preoperative topography and aberration are essential for understanding indications for LALs. Furthermore, when determining intraocular lens power, it is crucial to factor in potential postoperative myopia or hyperopic adjustments. This is achieved by establishing a proper postimplantation refractive target and considering potential wavefront changes. Postoperative adjustments for defocus and astigmatism have demonstrated excellent outcomes. Monovision strategy by adjustable blended vision of LALs revealed distance vision of 20/20 along with near vision of J2 in 96% of patients. However, the results of clinical studies on postrefractive cataract surgery showed contrasting outcomes at distance, indicating the need for further research results regarding its effectiveness. A new postoperative workflow needs to be designed to enable a systematic follow-up process.

SUMMARY

LALs are safe and demonstrate promising refractive outcomes. To achieve appropriate results, understanding the changes in optical characteristics associated with adjustment and constructing a new postoperative workflow are necessary.

Efficacy of cataract surgeries performed during blindness prevention programs in Chongqing, China: a multicenter prospective study

OBJECTIVE

To determine the efficacy of cataract surgeries in blindness prevention programs in Chongqing.

METHODS

During February-December 2019, we prospectively enrolled 487 patients (592 eyes) undergoing cataract surgery during blindness prevention programs in 6 Chongqing district/county hospitals (experimental group) and 481 patients (609 eyes) undergoing cataract surgery in the First Affiliated Hospital of Chongqing Medical University (controls). Uncorrected visual acuity (UCVA), refractive status, best corrected visual acuity (BCVA), slit lamp examination, and visual function/quality of life (VF-QOL) questionnaire scores were evaluated preoperatively, and at 1 and 6 months postoperatively.

RESULTS

In the experimental group, UCVA, BCVA, and VF-QOL scores at 1 and 6 months were better than the preoperative values (P < 0.05), but lower than the control-group values (P < 0.05). Rates of good UCVA and BCVA outcomes (≤ 0.5 logMAR) in the experimental group were 76.2% and 87.6%, respectively, at 1 month and 68.9% and 83.1%, respectively, at 6 months. Most eyes in the experimental (82.1%) and control (89.5%) groups had refractive errors within ± 1 D at 1 month. At 6 months, posterior capsule opacification (PCO) was more common in the experimental group (20.9% vs. 15.0%, P < 0.05). At 6 months, the main causes of visual impairment (UCVA > 0.5 logMAR) in the experimental group were uncorrected refractive errors (33.0%), PCO (29.5%), and fundus diseases (33.9%).

CONCLUSION

Cataract surgeries in blindness prevention programs in Chongqing significantly improved visual acuity, VF, and QOL, but underperformed compared to surgeries in the tertiary teaching hospital.

Comparison of the Rate of Posterior Capsule Opacification Following Combined Treatment With Topical Dexamethasone 0.1% Plus Ketorolac 0.5% Eye Drops Versus Dexamethasone 0.1% Alone: A Two-Year, Randomized Clinical Investigation

Background and aim The use of non-steroidal anti-inflammatory drugs in animals decreases the incidence of posterior capsular opacification (PCO) following cataract surgery. We evaluated the rate of PCO in patients with cataract surgery and foldable "in the bag" posterior chamber intraocular lens (PC-IOL) implantation treated with combined dexamethasone 0.1% plus ketorolac tromethamine 0.5% versus dexamethasone 0.1% alone. Materials and methods A total of 114 eyes of 101 patients underwent uneventful corneal small-incision phacoemulsification with primary implantation of a foldable acrylic PC-IOL (AcrySof^®, Alcon, Fort Worth, USA). Postoperatively for four weeks, group 1 eyes were treated with dexamethasone 0.1% plus ketorolac tromethamine 0.5% ophthalmic solutions four times daily for each whereas group 2 eyes were treated with dexamethasone 0.1% alone. Other regiments were the same for each group. Patients were evaluated between one- and four-year following surgery. The frequency and timing of severe PCO following surgery that needed Nd:YAG laser posterior capsulotomy were recorded and evaluated. Results The mean (SEM) age of group 1 (n = 54) and group 2 (n = 60) at operation was similar (62.8 ± 2.2 vs. 60.6 ± 1.7 years, respectively). Eighty-eight patients had unilateral cataract and 13 cases had bilateral disease. Overall, the mean follow-up duration was 24.7 months postoperatively (range, 15-48). Clinically significant PCO that finally needed Nd:YAG laser application developed in two eyes (3.7%) in group 1 and in four eyes (6.6%) in group 2, and the difference was not statistically significant (p>0.05). The mean month at capsulotomy was 26.5 in group 1 and 24.3 months in group 2 eyes (p>0.05). Conclusions Topical instillation of ketorolac ophthalmic solution in the immediate period after phacoemulsification and PC-IOL implantation did not seem to influence the incidence of PCO formation two years after cataract surgery.

Evaluation of Nd:YAG laser capsulotomy results in patients who underwent cataract extraction and intraocular lens implantation with the endocapsular phacoemulsification method

Background/Aim: Posterior capsular opacification (PCO) is a common complication that develops after cataract surgery, and it can be treated neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy. In this study, we aimed to investigate the effects of different intraocular lenses (IOLs) on the development of posterior capsule opacification (PCO), to determine the time between surgery and Nd:YAG laser capsulotomy, and to evaluate the efficacy, effectiveness, and complications of capsulotomy in patients who underwent cataract surgery with the phacoemulsification method and subsequently developed PCO. Methods: The cohort study included one eye of each of 153 cases (63 males, 90 females) who underwent cataract surgery with the phacoemulsification method in our clinic from August 1, 2006, through August 1, 2008, and subsequently developed PCO. According to the type of IOL implanted, the cases were divided into three groups: polymethylmethacrylate IOL (Group 1), hydrophilic acrylic IOL (Group 2), and hydrophobic acrylic IOL (Group 3). The control examinations of the patients who underwent Nd:YAG laser capsulotomy were undertaken before capsulotomy and at the first week, first month, and third month after capsulotomy. Results: Visual acuity improvement was detected in 96.7% of the 153 cases. It was determined that 9.1% of the cases had an intraocular pressure (IOP) increase of more than 5 mmHg at the third hour after capsulotomy and approached baseline values at the end of 1 week. The mean   total energy used in all the cases was 37.20 (14.70) mjl. The mean total energy used in 14 patients with an IOP elevation of above 5 mmHg was 71.07 (10.59) mjl. Nd:YAG laser capsulotomy was performed at an average of 6.29 (4.91) months in Group 1, 7.81 (4.35) months in Group 2, and 17.7 (12.35) months in Group 3. After capsulotomy, clinically significant cystoid macular edema was observed in 1.9% of the cases, IOL damage in 3.9%, and vitreous hemorrhage in 0.6%. Conclusion: In this study, the incidence of PCO development was found to be lower in the patients who underwent hydrophobic acrylic IOL implantation; therefore, this type of lens should be preferred for implantation. Although Nd:YAG laser capsulotomy is an outpatient treatment method that can be applied quickly and can increase visual acuity, it can also lead to complications. To eliminate most of these complications, it would be beneficial to minimize the energy used during the laser procedure.